Two animal models of aggression shock elicited fighting, and food induced fighting - are used to investigate the role of known neurotransmitter systems in the control of aggressive behaviors. Rats and mice are the subjects of the research. Drugs which have a specific effect on neurotransmitter systems are used to investigate their effects on aggressive behavior in these two models. The significance is that a thorough knowledge of the neurochemical control of aggressive behavior will lead to a rational psychopharmacology of aggressive behavior in man.